The prior art contains various examples of walled structures that are designed to capture or rebound a ball. An early example is shown in the U.S. Pat. No. 1,540,670 to Vidmer which discloses a netted enclsoure having a relatively large open front end, and upper, lower left and right side walls extending to a relatively small back wall. As disclosed by Vidmer, the netting is rigged to a supporting structure and to ground. He contemplates that the walls should be drawn taut, but it appears clear that the only way of achieving a desired degree of tautness or tension would be by means of several individual adjustments.
More recent examples of structures designed to capture or rebound a ball are shown in U.S. Pat. No. 4,381,110 to Balaz and U.S. Pat. No. 4,703,931 to Steen. In the case of Balaz, tensioning of upper and lower side walls and a back wall is achieved by spreading the sides of a collapsible V-shaped frame. However, to set tension in these walls, manual adjustment and setting is required at upper and lower locations, and it appears that independent adjustment of the rigging would be required in order to vary the tension in left and right side walls.
The patent to Steen similarly discloses an enclosure having a back wall and upper, lower, left and right side walls and a back wall. In this case, tensioning is achieved by a rather complex rigging arrangement which in principle is designed to pull outwardly and rearwardly from the back wall of the enclosure towards corners of a supporting framework that are fixed in position. However, the rigging is intricate and, unless properly adjusted, it is possible to have a relatively high degree of imbalance of tension between respective side walls. In such a case, the deflection when a ball strikes one of such side walls may be undesirably different from the corresponding deflection when a ball strikes another one of such side walls. Further, the rigging would become even more complex if the number of side walls was increased.
It is an object of the present invention to provide new and improved apparatus for supporting and tensioning a net.
A further object of the present invention is to provide a net tensioning means which requires a minimal number of adjustments to vary or adjust the tension.
Yet another object of the present invention is to provide a net tensioning mechanism that requires a minimal amount of rigging, and which is readily adaptable to net designs having four or more sidewalls.